Information processing device, information processing method, and program

ABSTRACT

The purpose of the invention is to provide an information processing device including a first reception unit which receives from a plurality of secondary battery management systems, charge/discharge data of secondary batteries managed by the secondary battery management systems, and an estimation model generation unit which generates an estimation model for estimating a degradation indicator indicating a state of degradation of the secondary battery based on the charge/discharge data.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/JP2021/007491, filed Feb. 26, 2021, and International ApplicationNo. PCT/JP2020/030800, filed Aug. 13, 2020, the entire contents of whichare incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an information processing device, aninformation processing method, and a program.

BACKGROUND ART

In recent years, a technology for converting natural energy such assunlight or wind power into electrical energy has been attractingattention. Along with this, various secondary batteries have beendeveloped as storage devices which are high in safety and capable ofstoring a large amount of electrical energy. In particular, a secondarybattery using a negative electrode having no negative electrode activematerial such as a carbon material or a lithium metal has been developedfor the purpose of achieving higher energy density and improvingproductivity as compared with a lithium ion secondary battery or thelike. There has been disclosed in, for example, Japanese UnexaminedPatent Application Publication No. 2019-25971, a secondary battery inwhich metal particles are formed on a negative electrode currentcollector and are moved from a positive electrode by charging to form alithium metal on the negative electrode current collector.

Since such a secondary battery is degraded as it is repeatedly chargedand discharged during use, various estimation methods for thedegradation state of the secondary battery have been proposed. In thisregard, the present inventors have found that, for the secondary batterywhich does not have the negative electrode active material describedabove, the degradation state shows various parameters of the secondarybattery and good linearity.

SUMMARY OF INVENTION

However, for example, in estimating a degradation state of a secondarybattery, it may be difficult to perform the estimation highly accuratelyeven if the estimation is performed based only on data obtained from thesecondary battery. On the other hand, in

BaaS (Battery as a Service) which comprehensively provides variousservices related to the use of secondary batteries to plural users,there is an aspect that data of the secondary batteries used by eachuser is not fully utilized.

The present invention has been made in view of such circumstances, andan object thereof is to provide an information processing device, aninformation processing method, and a program capable of effectivelyutilizing data on a plurality of secondary batteries and predicting adegradation state of the secondary batteries with high accuracy.

An information processing device according to an aspect of the presentinvention includes a first reception unit which receives from aplurality of secondary battery management systems, charge/discharge dataof secondary batteries managed by the secondary battery managementsystems, and an estimation model generation unit which generates anestimation model for estimating a degradation indicator indicating astate of degradation of each secondary battery based on thecharge/discharge data.

According to this aspect, after receiving from a plurality of secondarybattery management systems, charge/discharge data of secondary batteriesmanaged by the secondary battery management systems, it is possible togenerate an estimation model for estimating a degradation indicator ofthe secondary battery based on these charge/discharge data. Therefore,it is possible to effectively utilize data related to a plurality ofsecondary batteries and predict a degradation state of the secondarybatteries with high accuracy.

According to the present invention, it is possible to provide aninformation processing device, an information processing method, and aprogram capable of effectively utilizing data related to a plurality ofsecondary batteries and predicting a degradation state of the secondarybatteries with high accuracy.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an example of a schematicconfiguration of a management system 1 according to the presentembodiment;

FIG. 2 is a block diagram showing an example of a schematicconfiguration of a power supply device 10 according to the presentembodiment;

FIG. 3 is a schematic cross-sectional view of a lithium secondarybattery 101 according to the present embodiment;

FIG. 4 is a block diagram showing an example of a functionalconfiguration of a BMS 400 according to the present embodiment;

FIG. 5 is a block diagram showing an example of a functionalconfiguration of a server device 20 according to the present embodiment;

FIG. 6 is a diagram showing an example of a data structure ofcharge/discharge data according to the present embodiment;

FIG. 7 is a diagram showing characteristic information of “OCV afterdischarge” and “SOH” of the lithium secondary battery 101 according tovarious examples;

FIG. 8 is a diagram showing characteristic information of “OCV aftercharge-OCV after discharge” and “charge/discharge capacity” of thelithium secondary battery 101 according to various examples;

FIG. 9 is a diagram showing an example of an operation sequence of ageneration process of an estimation model by the management system 1according to the present embodiment;

FIG. 10 is a diagram showing an example of an operation sequence of anestimation process of a degradation indicator by the management system 1according to the present embodiment; and

FIG. 11 is a diagram showing an example of a screen 1000 of notificationinformation according to the present embodiment.

DETAILED DESCRIPTION

Preferred embodiments of the present invention will be described withreference to the accompanying drawings. Incidentally, in each figure,those designated at the same reference numerals have the same or similarconfigurations.

(1) Management System 1

FIG. 1 is a block diagram showing an example of a schematicconfiguration of a management system 1 according to the presentembodiment. As shown in FIG. 1 , the management system 1 includes, forexample, a plurality of power supply devices 10 and a server device 20.Each of the power supply devices 10 is a power supply device used by auser and includes, for example, a battery module 100, a charger 200, aload 300, and a battery management system (BMS) 400. Each BMS 400 andthe server device 20 are connected to a communication network N such asthe Internet so that information can be transmitted and received to eachother, for example. In the management system 1, for example, the serverdevice 20 provides BaaS (Battery as a Service) which comprehensivelyprovides various services related to the use of a secondary battery toeach user who uses the power supply device 10.

(2) Power Supply Device 10

(2-1) Overall Configuration

FIG. 2 is a block diagram showing an example of a schematicconfiguration of the power supply device 10 according to the presentembodiment.

The power supply device 10 includes, for example, a battery module 100,a charger 200, a load 300, and a BMS 400.

The battery module 100 includes a lithium secondary battery 101 as asingle cell, or a plurality of lithium secondary batteries 101 connectedin series and/or in parallel. The number of the lithium secondarybatteries 101 included in the battery module 100 is not limited inparticular. The lithium secondary batteries 101 may respectively havethe same characteristics or may respectively have differentcharacteristics. The details of the configuration of the lithiumsecondary battery 101 will be described later.

The battery module 100 further has a current sensor 102 connected inseries to the lithium secondary batteries 101. The current sensor 102 isconnected in series to the lithium secondary batteries 101. The currentsensor 102 measures a current flowing through these lithium secondarybatteries 101 and supplies its current value to the BMS 400.

The battery module 100 further has a voltage sensor 103 and atemperature sensor 104 provided in each of the lithium secondarybatteries 101. Each voltage sensor 103 is connected in parallel to thelithium secondary battery 101. The voltage sensor 103 measures thevoltage (inter-terminal voltage) between a positive electrode terminaland a negative electrode terminal of the lithium secondary battery 101and supplies its voltage value to the BMS 400. Further, the temperaturesensor 104 is thermally coupled to each of the lithium secondarybatteries 101, and measures the temperature of the lithium secondarybattery 101 and supplies its temperature value to the BMS 400.

The configuration of the charger 200 is not limited in particular, butthe charger 200 may be configured to be provided with, for example, acharging connector to which a charging plug connected to an externalpower supply can be connected, and to convert power supplied from theexternal power supply into charging power of the lithium secondarybattery 101. The lithium secondary battery 101 is connected to thecharger 200, for example, and can be charged by a charging currentsupplied by the charger 200 under the control of the BMS 400.

The configuration of the load 300 is not limited in particular, but itmay be configured as, for example, a drive device of an electric vehicle(electric car, hybrid car), or the like. The lithium secondary battery101 is connected to the load 300, for example, and can supply a currentto the load 300 under the control of the BMS 400.

The BMS 400 controls the charging and discharging of the lithiumsecondary battery 101 included in the battery module 100. Theconfiguration of the BMS 400 will be described later.

(2-2) Lithium Secondary Battery 101

FIG. 3 is a schematic cross-sectional view of the lithium secondarybattery 101 according to the present embodiment. The lithium secondarybattery 101 of the present embodiment includes a positive electrode 12and a negative electrode 13 having no negative electrode activematerial. Further, in the lithium secondary battery 101, a positiveelectrode current collector 11 is arranged on the side opposite to thesurface of the positive electrode 12 facing the negative electrode 13,and a separator 14 is arranged between the positive electrode 12 and thenegative electrode 13. Hereinafter, each configuration of the lithiumsecondary battery 101 will be described.

(Negative Electrode)

The negative electrode 13 has no negative electrode active material. Inthe present specification, the “negative electrode active material” is asubstance which causes an electrode reaction, that is, an oxidationreaction and a reduction reaction at the negative electrode.Specifically, the negative electrode active material of the presentembodiment may include a lithium metal and a host substance of a lithiumelement (lithium ion or lithium metal). The host substance of thelithium element means a substance provided for holding lithium ions orthe lithium metal in the negative electrode 13. A mechanism for suchholding is not limited in particular, but may include, for example,intercalation, alloying, and occlusion of metal clusters, and the like,typically, intercalation.

In the lithium secondary battery 101 of the present embodiment, sincethe negative electrode 13 does not have the negative electrode activematerial before the initial charging of the battery, the lithium metalis precipitated on the negative electrode 13, and the precipitatedlithium metal is electrolytically eluted so that charging anddischarging are performed. Therefore, in the lithium secondary battery101 of the present embodiment, the volume occupied by the negativeelectrode active material and the mass of the negative electrode activematerial are reduced as compared with the lithium secondary battery 101having the negative electrode active material, and the volume and massof the entire battery are reduced, so that the energy density is high inprinciple.

In the lithium secondary battery 101 of the present embodiment, thenegative electrode 13 does not have the negative electrode activematerial before the initial charging of the battery, the lithium metalis precipitated on the negative electrode by charging of the battery,and the precipitated lithium metal is electrolytically eluted bydischarging of the battery. Therefore, in the lithium secondary battery101 of the present embodiment, the negative electrode 13 does notsubstantially have the negative electrode active material even at theend of discharging of the battery. Therefore, in the lithium secondarybattery 101 of the present embodiment, the negative electrode 13 acts asa negative electrode current collector.

Comparing the lithium secondary battery 101 of the present embodimentwith a lithium ion battery (LIB) and a lithium metal battery (LMB), theyare different in the following points.

In the lithium ion battery (LIB), the negative electrode has a hostsubstance of a lithium element (lithium ion or lithium metal), thesubstance is filled with the lithium element by charging of the battery,and the host substance releases the lithium element so that the batteryis discharged. The LIB differs from the lithium secondary battery 101 ofthe present embodiment in that the negative electrode has the hostsubstance of the lithium element.

The lithium metal battery (LMB) is manufactured by using an electrodehaving a lithium metal on its surface or a lithium metal alone as anegative electrode. That is, the LMB differs from the lithium secondarybattery 101 of the present embodiment in that the negative electrode hasa lithium metal which is a negative electrode active materialimmediately after assembling the battery, that is, before the initialcharging of the battery. The LMB uses an electrode containing a lithiummetal high in flammability and reactivity for its production, but thelithium secondary battery 101 of the present embodiment is more superiorin safety and productivity because it uses the negative electrode 13having no lithium metal.

In the present specification, the term “the negative electrode has nonegative electrode active material” means that the negative electrodedoes not have or substantially does not have the negative electrodeactive material. The fact that the negative electrode has substantiallyno negative electrode active material means that the content of thenegative electrode active material in the negative electrode is 10% bymass or less with respect to the entire negative electrode. The contentof the negative electrode active material in the negative electrode ispreferably 2% by mass or less with respect to the entire negativeelectrode, and may be 1.0% by mass or less, 0.1% by mass or less, or0.0% by mass or less. When the negative electrode does not have thenegative electrode active material or the content of the negativeelectrode active material in the negative electrode is within the aboverange, the energy density of the lithium secondary battery 101 becomeshigh.

In the present specification, the term “the lithium metal isprecipitated on the negative electrode” means that the lithium metal isprecipitated on the surface of the negative electrode or at least oneplace on the surface of a solid electrolyte interface (SEI) layer to bedescribed later formed on the surface of the negative electrode. Forexample, in FIG. 1 , the lithium metal is precipitated on the surface ofthe negative electrode 13 (the interface between the negative electrode13 and the separator 14).

In the present specification, the term “before the battery is initiallycharged” means a state from the time when the battery is assembled tothe time when the battery is charged for the first time. Further, theterm “at the end of discharging” of the battery means a state in whichthe voltage of the battery is 1.0 V or more and 3.8 V or less,preferably 1.0 V or more and 3.0 V or less.

In the present specification, the term, “the lithium secondary battery101 having the negative electrode having no negative electrode activematerial” means that the negative electrode does not have the negativeelectrode active material before the initial charging of the battery orat the end of its discharging. Therefore, the phrase “the negativeelectrode having no negative electrode active material” may beparaphrased with “a negative electrode having no negative electrodeactive material before the initial charging of the battery or at the endof its discharging”, “a negative electrode having no negative electrodeactive material other than the lithium metal regardless of the state ofcharging of the battery and having no lithium metal before the initialcharging or at the end of discharging”, or “a negative electrode currentcollector having no lithium metal before the initial charging or at theend of discharging”, or the like. Further, the term “the lithiumsecondary battery 101 including the negative electrode having nonegative electrode active material” may be paraphrased with ananode-free lithium battery, a zero anode lithium battery, or ananodeless lithium battery.

In the negative electrode 13 of the present embodiment, the content ofthe negative electrode active material other than the lithium metal is10% by mass or less with respect to the entire negative electroderegardless the state of charging of the battery, preferably 2% by massor less, and may be 1.0% by mass or less, 0.1% by mass or less, or 0.0%by mass or less. Further, in the negative electrode 13 of the presentembodiment, before the initial charging or at the end of discharging,the content of the lithium metal is 10% by mass or less with respect tothe entire negative electrode, preferably 2% by mass or less, and may be1.0% by mass or less, 0.1% by mass or less, or 0.0% by mass or less. Thenegative electrode 13 preferably has a lithium metal content of 10% bymass or less with respect to the entire negative electrode 13 beforeinitial charging and at the end of discharging (even among this range,preferably, the content of the lithium metal is 2% by mass or less withrespect to the entire negative electrode 13, and may be 1.0% by mass orless, 0.1% by mass or less, or 0.0% by mass or less.).

In the lithium secondary battery 101 of the present embodiment, when thevoltage of the battery is 1.0 V or more and 3.5 V or less, the contentof the lithium metal may be 10% by mass or less with respect to theentire negative electrode 13 (preferably 2% by mass or less, and may be1.0% by mass or less, 0.1% by mass or less, or 0.0% by mass or less);when the voltage of the battery is 1.0 V or more and 3.0 V or less, thecontent of the lithium metal may be 10% by mass or less with respect tothe entire negative electrode 13 (preferably 2% by mass or less, and maybe 1.0% by mass or less, 0.1% by mass or less, or 0.0% by mass or less);or when the voltage of the battery is 1.0 V or more and 2.5 V or less,the content of the lithium metal may be 10% by mass or less with respectto the entire negative electrode (preferably 2% by mass or less, and maybe 1.0% by mass or less, 0.1% by mass or less, or 0.0% by mass or less).

Further, in the lithium secondary battery 101 of the present embodiment,a ratio M3.0/M4.2 of a mass M3.0 of the lithium metal precipitated onthe negative electrode 13 in the state in which the voltage of thebattery is 3.0 V, to a mass M4.2 of the lithium metal precipitated onthe negative electrode 13 in the state in which the voltage of thebattery is 4.2 V, is preferably 20% or less, more preferably 15% orless, still more preferably 10% or less. The ratio M3.0/M4.2 may be 8.0%or less, 2% or less, 3.0% or less, or 1.0% or less.

As examples of the negative electrode active material of the presentembodiment, there may be mentioned a lithium metal and an alloycontaining the lithium metal, a carbon-based substance, a metal oxide, ametal alloyed with lithium, and an alloy containing the metal, etc. Thecarbon-based substance is not limited in particular, but may include,for example, graphene, graphite, hard carbon, mesoporous carbon, carbonnanotubes, and carbon nanohorns, etc. The metal oxide is not limited inparticular, but may include, for example, a titanium oxide-basedcompound, a tin oxide-based compound, and a cobalt oxide-based compound,etc. The metal alloyed with the lithium may include, for example,silicon, germanium, tin, lead, aluminum, and gallium.

The negative electrode 13 in the present embodiment is not particularlylimited as long as it does not have a negative electrode active materialand can be used as a current collector, but may include at least onetype selected from a group consisting of, for example, Cu, Ni, Ti, andFe, other metals which do not react with Li, an alloy of these, andstainless steel (SUS). Incidentally, when SUS is used for the negativeelectrode 13, various conventionally known types can be used as the typeof SUS. As the negative electrode material as described above, one typeis used alone or two or more types are used in combination.Incidentally, in the present specification, the term “the metal whichdoes not react with Li” means a metal which does not react with thelithium ions or lithium metal to form an alloy under the operatingconditions of the lithium secondary battery 101.

The negative electrode 13 of the present embodiment preferably consistsof at least one type selected from a group consisting of Cu, Ni, Ti, andFe, an alloy of these, and stainless steel (SUS). More preferably, itconsists of at least one type selected from a group consisting of Cu andNi, an alloy of these, and stainless steel (SUS). Further preferably,the negative electrode 13 is Cu and Ni, an alloy of these, or thestainless steel (SUS). When such a negative electrode 13 is used, theenergy density and productivity of the battery tend to be even moreexcellent.

The average thickness of the negative electrode 13 is preferably 4 μm ormore and 20 μm or less, more preferably 5 μm or more and 18 μm or less,and further preferably 6 μm or more and 15 μm or less. According to suchan aspect, the volume occupied by the negative electrode 13 in thebattery is reduced, so that the energy density of the battery is furtherimproved.

(Positive Electrode)

As long as the positive electrode 12 has a positive electrode activematerial, the positive electrode 12 is not particularly limited as longas it is generally used for the lithium secondary battery 101, but theknown material can be appropriately selected depending on the use of thelithium secondary battery 101. The positive electrode 12 is high instability and output voltage because it has the positive electrodeactive material.

In the present specification, the term “the positive electrode activematerial” means a substance which causes an electrode reaction, that is,an oxidation reaction and a reduction reaction at the positiveelectrode. Specifically, the positive electrode active material of thepresent embodiment may include a host material of a lithium element(typically, lithium ion).

Such a positive electrode active material is not limited in particular,but may include, for example, a metal oxide and a metal phosphate. Themetal oxide is not limited in particular, but may include, for example,a cobalt oxide-based compound, a manganese oxide-based compound, and anickel oxide-based compound, etc. The metal phosphate is not limited inparticular, but may include, for example, an iron phosphate-basedcompound and a cobalt phosphate-based compound. A typical positiveelectrode active material may include LiCoO2, LiNixCoyMnzO (x+y+z=1),LiNixMnyO (x+y=1), LiNiO2, LiMn2O4, LiFePO, LiCoPO, LiFeOF, LiNiOF, andTiS2. As the positive electrode active material as described above, onetype is used alone or two or more types are used in combination.

The positive electrode 12 may contain components other than theabove-mentioned positive electrode active material. Such components arenot limited in particular, but may include, for example, a knownconductive assistant, a binder, a polymer electrolyte, and an inorganicsolid electrolyte.

The conductive assistant in the positive electrode 12 is not limited inparticular, but may include, for example, a carbon black, a single-wallcarbon nanotube (SWCNT), a multi-wall carbon nanotube (MWCNT), a carbonnanofiber (CF), and an acetylene black, etc. Further, the binder is notlimited in particular, but may include, for example, polyvinylidenefluoride, polytetrafluoroethylene, styrene-butadiene rubber, an acrylicresin, and a polyimide resin, etc.

The content of the positive electrode active material in the positiveelectrode 12 may be, for example, 2% by mass or more and 100% by mass orless with respect to the entire positive electrode 12. The content ofthe conductive assistant may be, for example, 0.5% by mass and 30% bymass or less with respect to the entire positive electrode 12. Thecontent of the binder may be, for example, 0.5% by mass and 30% by massor less with respect to the entire positive electrode 12. The totalcontent of the solid polyelectrolyte and the inorganic solid electrolytemay be, for example, 0.5% by mass and 30% by mass or less with respectto the entire positive electrode 12.

(Positive Electrode Current Collector)

The positive electrode current collector 11 is arranged on one side ofthe positive electrode 12. The positive electrode current collector 11is not particularly limited as long as it is a conductor which does notreact with lithium ions in the battery. As such a positive electrodecurrent collector 11, there is mentioned, for example, aluminum.

The average thickness of the positive electrode current collector 11 ispreferably 4 μm or more and 20 μm or less, more preferably 5 μm or moreand 18 μm or less, and further preferably 6 μm or more and 15 μm orless. According to such an aspect, the volume occupied by the positiveelectrode current collector 11 in the lithium secondary battery 101 isreduced, so that the energy density of the lithium secondary battery 101is further improved.

(Separator)

The separator 14 is a member for ensuring the ionic conductivity oflithium ions which become charge carriers between the positive electrode12 and the negative electrode 13, while preventing the battery fromshort-circuiting by separating the positive electrode 12 and thenegative electrode 13 from each other. The separator 14 is made of amaterial which does not have electron conductivity and does not reactwith the lithium ions. Further, the separator 14 also assumes a role ofholding an electrolytic solution. Although the material itselfconstituting the separator 14 does not have ionic conductivity, theseparator 14 holds the electrolytic solution, so that the lithium ionsare conducted through the electrolytic solution. The separator 14 is notlimited as long as it plays the above role, but is composed of, forexample, a porous polyethylene (PE) film, a polypropylene (PP) film, ora laminated structure thereof.

The separator 14 may be covered with a separator coating layer. Theseparator coating layer may cover both sides of the separator 14 or maycover only one side thereof. The separator coating layer is notparticularly limited as long as it is a member which does not react withthe lithium ions, but it is preferable that the separator 14 and thelayer adjacent to the separator 14 can be firmly adhered to each other.Such a separator coating layer is not limited in particular, but mayinclude those containing binders like, for example, polyvinylidenefluoride (PVDF), a mixture of styrene-butadiene rubber and carboxymethylcellulose (SBR-CMC), polyacrylic acid (PAA), lithium polyacrylic acid(Li-PAA), polyimide (PI), polyamideimide (PAI), and aramid. In theseparator coating layer, inorganic particles such as silica, alumina,titania, zirconia, magnesium oxide, magnesium hydroxide, and lithiumnitrate, etc. may be added to the binder. Incidentally, the separator 14may not have the separator coating layer or may have the separatorcoating layer.

The average thickness of the separator 14 is preferably 30 μm or less,more preferably 25 μm or less, and further preferably 20 μm or less.According to such an aspect, since the volume occupied by the separator14 in the lithium secondary battery 101 is reduced, the energy densityof the lithium secondary battery 101 is further improved. Further, theaverage thickness of the separator 14 is preferably 5 μm or more, morepreferably 7 μm or more, and further preferably 10 μm or more. Accordingto such an aspect, the positive electrode 12 and the negative electrode13 can be more reliably isolated from each other, and theshort-circuiting of the battery can be further suppressed.

(Electrolytic Solution)

The lithium secondary battery 101 preferably has an electrolyticsolution. In the lithium secondary battery 101, the electrolyticsolution may be infiltrated into the separator 14, or may be enclosed ina closed container together with a laminate of the positive electrodecurrent collector 11, the positive electrode 12, the separator 14, andthe negative electrode 13. The electrolytic solution is a solutioncontaining an electrolyte and a solvent and having ionic conductivityand acts as a conductive path for the lithium ions. Therefore, accordingto the aspect including the electrolytic solution, the internalresistance of the battery is further reduced, and the energy density,capacity, and cycle characteristics thereof are further improved.

The electrolytic solution preferably contains a fluoroalkyl compoundhaving at least one of a monovalent group represented by the followingformula (A) and a monovalent group represented by the following formula(B) as a solvent.

However, in the formula, a wavy line represents a binding site in themonovalent group.

Generally, in an anode-free lithium secondary battery 101 having anelectrolytic solution, a solid electrolyte interface layer (SEI layer)is formed on the surface of the negative electrode or the like bydecomposing the solvent or the like in the electrolytic solution. TheSEI layer suppresses further decomposition of the components in theelectrolytic solution in the lithium secondary battery 101, irreversiblereduction of lithium ions due to the decomposition, and the generationof gas, etc. Further, since the SEI layer has ionic conductivity, thereactivity of the lithium metal precipitation reaction becomes uniformin the surface direction of the negative electrode surface on thenegative electrode surface on which the SEI layer is formed. When theabove-mentioned fluoroalkyl compound is used as the solvent in thelithium secondary battery 101, the SEI layer is likely to be formed onthe surface of the negative electrode, and the growth of a dendrite-likelithium metal on the negative electrode is further suppressed, thusresulting in the cycle characteristics tending to be further improved.

Incidentally, in the present specification, the term “the compound is“contained as the solvent” means that the compound alone or a mixturewith another compound may be liquid in the usage environment of thelithium secondary battery 101, and further, an electrolyte may bedissolved to enable an electrolytic solution in a solution phase to beproduced.

Such a fluoroalkyl compound may include a compound having an ether bond(hereinafter referred to as an “ether compound”), a compound having anester bond, and a compound having a carbonate bond, etc. The fluoroalkylcompound is preferably an ether compound from the viewpoint of furtherimproving the solubility of the electrolyte in the electrolytic solutionand the viewpoint of further facilitating the formation of the SEIlayer.

The ether compound which is of the fluoroalkyl compound may include, anether compound having both the monovalent group represented by theformula (A) and the monovalent group represented by the formula (B)(also called, a “first fluorine solvent”), an ether compound having themonovalent group represented by the formula (A) and having no monovalentgroup represented by the formula (B) (also called a “second fluorinesolvent”), and an ether compound having no monovalent group representedby the formula (A) and having the monovalent group represented by theformula (B) (also called, a “third fluorine solvent”), and the like.

The first fluorine solvent may include1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether,1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyldiethoxymethane, and1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyldiethoxypropane, andthe like. From the viewpoint of effectively and surely exerting theeffect of the above-mentioned fluoroalkyl compound,1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether is preferableas the first fluorine solvent.

The second fluorine solvent may include, for example,1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether,methyl-1,1,2,2-tetrafluoroethyl ether, ethyl-1,1,2,2-tetrafluoroethylether, propyl-1,1,2,2-tetrafluoroethyl ether,1H,1H,5H-perfluoropentyl-1,1,2,2-tetrafluoroethyl ether, and1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and the like.From the viewpoint of effectively and surely exerting the effect of theabove-mentioned fluoroalkyl compound,1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether,methyl-1,1,2,2-tetrafluoroethyl ether, ethyl-1,1,2,2-tetrafluoroethylether, and 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether arepreferable as the second fluorine solvent.

The third fluorine solvent may include, for example,difluoromethyl-2,2,3,3-tetrafluoropropyl ether,trifluoromethyl-2,2,3,3-tetrafluoropropyl ether,fluoromethyl-2,2,3,3-tetrafluoropropyl ether, andmethyl-2,2,3,3-tetrafluoropropyl ether, and the like. From the viewpointof effectively and surely exerting the effect of the above-mentionedfluoroalkyl compound, difluoromethyl-2,2,3,3-tetrafluoropropyl ether ispreferable as the third fluorine solvent.

The electrolytic solution may contain a solvent having neither themonovalent group represented by the formula (A) nor the monovalent grouprepresented by the formula (B). Such a solvent is not particularlylimited, but may include, for example, solvents containing no fluorinesuch as dimethyl ether, triethylene glycol dimethyl ether,dimethoxyethane, diethylene glycol dimethyl ether, acetonitrile,dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylenecarbonate, propylene carbonate, chloroethylene carbonate, methylacetate, ethyl acetate, propyl acetate, methylpropionate, ethylpropionate, trimethyl phosphate, and triethyl phosphate, etc. , andsolvents containing the fluorine such as methyl nonafluorobutyl ether,ethyl nonafluorobutyl ether,1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-trifluoromethylpentane,methyl-2,2,3,3,3-pentafluoropropyl ether,1,1,2,3,3,3-hexafluoropropylmethyl ether,ethyl-1,1,2,3,3,3-hexafluoropropyl ether, and tetrafluoroethyltetrafluoropropyl ether, etc.

In the above-mentioned solvents including the above-mentionedfluoroalkyl compound, one type can be used alone, or two or more typescan be used in combination.

The content of the fluoroalkyl compound in the electrolytic solution isnot limited in particular, but is preferably 40% by volume or more, morepreferably 2% by volume or more, still more preferably 60% by volume ormore, or even more preferably 70% by volume or more with respect to thetotal amount of the solvent components of the electrolytic solution.When the content of the fluoroalkyl compound is within the above range,the SEI layer is more likely to be formed, so that the cyclecharacteristics of the battery tend to be further improved. The upperlimit of the content of the fluoroalkyl compound is not limited inparticular, and the content of the fluoroalkyl compound may be 100% byvolume or less, 95% by volume or less, 90% by volume or less, or 80% byvolume or less, with respect to the total amount of the solventcomponents of the electrolytic solution.

The electrolyte contained in the electrolytic solution is notparticularly limited as long as it is a salt, but may include, forexample, salts of Li, Na, K, Ca, and Mg, etc. As the electrolyte, alithium salt is preferably used. The lithium salt is not limited inparticular, but may include LiI, LiCl, LiBr, LiF, LiBF4, LiPF6, LiAsF6,LiSO3CF3, LiN (SO2F)2, LiN (SO2CF3)2, LiN (SO2CF3CF3)2, LiBF2 (C2O4),LiB (O2C2H4)2, LiB (O2C2H4)F2, LiB (OCOCF3)4, LiNO3, and Li2SO4, etc. Inthe above lithium salts, one type is used alone or two or more types areused in combination.

The concentration of the electrolyte in the electrolytic solution is notlimited in particular, but is preferably 0.5 M or more, more preferably0.7 M or more, still more preferably 0.9 M or more, or even morepreferably 1.0 M or more. When the concentration of the electrolyte iswithin the above range, the SEI layer is more likely to be formed, andthe internal resistance tends to be lower. The upper limit of theconcentration of the electrolyte is not particularly limited, and theconcentration of the electrolyte may be 10.0 M or less, 2 M or less, or2.0 M or less.

(2-3) BMS 400

FIG. 4 is a block diagram showing an example of a functionalconfiguration of the BMS 400 according to the present embodiment. TheBMS 400 is comprised of, for example, one or a plurality of computers,and has a communication unit 401, an operation unit 402, an output unit403, a storage unit 404, and a processing unit 405. The BMS 400 may be,for example, a device such as a PC, a smartphone, or a tablet terminal,and can manage the lithium secondary battery 101 and receive theprovision of BaaS from the server device 20.

The communication unit 401 includes a communication interface circuitand connects the BMS 400 to the communication network N. Thecommunication unit 401 transmits data supplied from the processing unit405 to the server device 20 and the like via the communication networkN. Further, the communication unit 401 supplies the data received fromthe server device 20 or the like via the communication network N to theprocessing unit 405.

The operation unit 402 may be any device as long as the BMS 400 can beoperated, for example, a touch panel, a key button, or the like. Theuser can input characters, numbers, symbols, etc. using the operationunit 402. When the operation unit 402 is operated by the user, theoperation unit 402 generates a signal corresponding to the operation.Then, the generated signal is supplied to the processing unit 405 as auser's instruction.

The output unit 403 includes, for example, a display unit and an audiooutput unit. The display unit may be any device as long as it candisplay a video, an image, or the like, and is, for example, a liquidcrystal display, an organic EL (Electro-Luminescence) display, or thelike. The display unit displays a video corresponding to video datasupplied from the processing unit 405, an image corresponding to imagedata, and the like. Further, the audio output unit is configured as, forexample, a speaker, and outputs audio based on audio data supplied fromthe processing unit 405.

The storage unit 404 includes, for example, a semiconductor memorydevice. The storage unit 404 stores an operating system program, adriver program, an application program, data, and the like used forprocessing in the processing unit 405. For example, the storage unit 404stores, as driver programs, an input device driver program whichcontrols the operation unit 402, an output device driver program whichcontrols the output unit 403, and the like. Further, the storage unit404 stores, as application programs, a program for managing the BMS 400,a program for using the BaaS provided by the server device 20, and thelike. Various programs may be installed in the storage unit 404 from,for example, a computer-readable portable recording medium such as aCD-ROM or a DVD-ROM by using a known setup program or the like. Further,the storage unit 404 may store charge/discharge data which is datarelated to charging/discharging of the lithium secondary battery 101managed by the BMS 400. A data structure of the charge/discharge datawill be described later.

The processing unit 405 includes one or a plurality of processors andtheir peripheral circuits. The processing unit 405 generally controlsthe overall operation of the BMS 400, and is, for example, a CPU. Theprocessing unit 405 controls the operations of the communication unit401, the output unit 403, and the like so that various processes of theBMS 400 are executed in an appropriate procedure based on the programstored in the storage unit 404 and the operation of the operation unit402, and the like. The processing unit 405 executes processing based onthe program (operating system program, driver program, applicationprogram, etc.) stored in the storage unit 404. Further, the processingunit 406 can execute a plurality of programs (application programs andthe like) in parallel.

The processing unit 405 includes, for example, a charge/dischargecontrol unit 406, a charge/discharge data generation unit 407, atransmission/reception unit 408, and an output control unit 409. Each ofthese units is a functional module realized by a program executed by theprocessor included in the processing unit 405. Alternatively, each ofthese units may be mounted in the BMS 400 as an independent integratedcircuit, a microprocessor, or firmware.

The charge/discharge control unit 406 controls charging and dischargingof each lithium secondary battery 101 included in the battery module100. The charge/discharge control unit 406 may control charging anddischarging based on, for example, a setting stored in advance in thestorage unit 404 or a setting input by an operation via the operationunit 402. The setting may be arbitrarily set depending on, for example,the time for charge/discharge, a residual capacity at the start ofcharge/discharge, a residual capacity at the end of charge/discharge, aterminal voltage of the positive electrode and/or negative electrode atthe start of charge/discharge, a terminal voltage of the positiveelectrode and/or negative electrode at the end of charge/discharge, etc.

The charge/discharge data generation unit 407 generates charge/dischargedata which is data related to the charging/discharging of the lithiumsecondary battery 101 managed by the BMS 400. The charge/discharge datageneration unit 407 may store the generated charge/discharge data in thestorage unit 404. The data structure of the charge/discharge data willbe described later.

The transmission/reception unit 408 has functions as a transmission unitand a reception unit, and transmits various information and data toother information processing devices such as the server device 20 viathe communication unit 401 and also receives various information anddata from other information processing devices such as the server device20 via the communication unit 401. The transmission/reception unit 408transmits, for example, charge/discharge data to the server device 20.Further, the transmission/reception unit 408 receives, for example,various notification information from the server device 20.

The output control unit 409 causes the output unit 403 to output variousinformation. For example, when the output unit 403 is configured as adisplay unit, the output control unit 409 generates video data or imagedata and causes the display unit to display a video based on the videodata, an image based on the image data, or the like. Further, when theoutput unit 409 is configured as an audio output unit, the outputcontrol unit 409 generates audio data and causes the audio output unitto output audio.

(3) Server Device 20

FIG. 5 is a block diagram showing an example of a functionalconfiguration of the server device 20 according to the presentembodiment. The server device 20 is, for example, an example of aninformation processing device comprised of one or a plurality ofcomputers, and includes a communication unit 21, a storage unit 22, anda processing unit 23. The server device 20 provides BaaS for each BMS400.

The communication unit 21 includes a communication interface circuit andconnects the server device 20 to the communication network N. Thecommunication unit 21 transmits the data supplied from the processingunit 23 to each BMS 400 or the like via the communication network N.Further, the communication unit 21 supplies the data received from eachBMS 400 or the like via the communication network N to the processingunit 23.

The storage unit 22 includes, for example, a semiconductor memorydevice. The storage unit 22 stores an operating system program, a driverprogram, an application program, data, and the like used for processingin the processing unit 23. The various programs may be installed in thestorage unit 22 from a computer-readable portable recording medium suchas a CD-ROM or a DVD-ROM, for example using a known setup program or thelike. The storage unit 22 may store, for example, an estimation modelgenerated by an estimation model generation unit 25. Also, the storageunit 22 may store the charge/discharge data transmitted from the BMS400. Further, the storage unit 22 may store information related to thespecifications of the battery module 100 managed by each BMS 400(information on the specifications of the lithium secondary battery 101such as the negative electrode, the positive electrode, the negativeelectrode current collector, the positive electrode current collector,the separator, and the electrolytic solution, and information about theconnection of each lithium secondary battery 101), and related to thespecifications of the charger 200 and the load 300, and the like.

The processing unit 23 includes one or a plurality of processors andtheir peripheral circuits. The processing unit 23 generally controls theoverall operation of the server device 20, and is, for example, a CPU.The processing unit 23 controls the operations of the communication unit21 and the like so that various processes of the server device 20 areexecuted in an appropriate procedure based on the program and the likestored in the storage unit 22. The processing unit 23 executesprocessing based on the program (operating system program, driverprogram, application program, or the like) stored in the storage unit22. Further, the processing unit 23 can execute a plurality of programs(application programs and the like) in parallel.

The processing unit 23 includes, for example, a transmission/receptionunit 24, an estimation model generation unit 25, an estimation unit 26,and a notification information generation unit 27. Each of these unitsis a functional module realized by a program executed by the processorincluded in the processing unit 23. Alternatively, each of these unitsmay be mounted in the server device 20 as an independent integratedcircuit, a microprocessor, or firmware.

The transmission/reception unit 24 has functions as a transmission unitand a reception unit, and transmits various information and data toother information processing devices such as each BMS 400 via thecommunication unit 21 and receives various information and data fromother information processing devices such as each BMS 400 via thecommunication unit 21. The transmission/reception unit 24 receives, forexample, charge/discharge data from each BMS 400. Further, thetransmission/reception unit 24 transmits, for example, variousnotification information to each BMS 400.

The estimation model generation unit 25 generates an estimation modelfor estimating a degradation indicator of the lithium secondary battery101 based on the charge/discharge data received from each BMS 400. Inparticular, the estimation model generation unit 25 may integratecharge/discharge data received from a plurality of BMS 400s to generatea single estimation model. The estimation model generation unit 25 maygenerate an estimation model as a regression formula model by, forexample, performing regression analysis based on the charge/dischargedata. Alternatively, the estimation model generation unit 25 maygenerate an estimation model as a machine-learned model by, for example,performing machine learning based on the charge/discharge data.

Here, description will be made about the data structure of thecharge/discharge data with reference to FIG. 6 . FIG. 6 is a diagramshowing an example of the data structure of the charge/discharge dataaccording to the present embodiment. Each record in a list shown in FIG.6 corresponds to one cycle of charging or discharging of the lithiumsecondary battery 101 included in the BMS 400. Incidentally, thecharge/discharge data further may include data on changes over time ineach cycle, of at least any one of the voltage value measured by thevoltage sensor 103, the current value measured by the current sensor102, and the temperature value measured by the temperature sensor 104.

As shown in FIG. 6 , the charge/discharge data includes, for example,the “date and time”, a “state”, a “mode”, “the number of cycles”, “thetotal number of cycles”, an “integrated capacity”, an “elapsed time”,“integrated power”, an “average voltage”, a “peak voltage”, an “OCV”, an“end condition”, and “analysis data” obtained by analyzingcharge/discharge data. The “date and time” is information indicating thedate and time when the cycle was executed. The “state” is informationindicating whether the cycle is for charging or discharging, forexample, 1 indicates charging and 2 indicates discharging. The “mode” isa mode setting related to repetition of charging and discharging. Forexample, “1” indicates a mode for executing a single charge/dischargecycle, and “2” indicates a mode for executing a plurality ofcharge/discharge cycles. The “number of cycles” is informationindicating how many cycles the cycle is in the mode indicated by the“mode”. The “total number of cycles” is information indicating the totalnumber of charge/discharge cycles executed in the power supply device10. The “integrated capacity” is information indicating the chargecapacity recorded by charging in the record or the discharge capacityrecorded by discharging in the record. The “elapsed time” is the timerequired for charging or discharging in the cycle. The “total elapsedtime” is the total elapsed time from the start of charging ordischarging of the power supply device 10 to the execution of chargingor discharging of the cycle. The “integrated power” is informationindicating the power charged by charging in the cycle or the powerdischarged by discharging in the cycle. The “average voltage” is theaverage voltage of the battery module 100 during charging or dischargingin the cycle. The “peak voltage” is the peak voltage (maximum value ofvoltage) of the battery module 100 during charging or discharging in thecycle. The “OCV” is information indicating an OCV after discharge, whichis an OCV after a predetermined time has elapsed since the end ofdischarging in the cycle, or an OCV after charging, which is an OCVafter a predetermined time has elapsed since the end of charging in thecycle. Here, the OCV is also referred to as an open circuit voltage(Open Circuit Voltage), and may be an equilibrium voltage when anexternal power supply is connected between the electrodes of the batteryand the current is set to 0 A and relaxed for a long time within a timerange in which self-discharging is not made. Incidentally, thepredetermined time may be, for example, the time required for the OCV tostabilize. The “end condition” is information indicating an endcondition of charging/discharging of the cycle. The end condition mayinclude, for example, that the voltage value of the lithium secondarybattery 101 has reached a predetermined value, or may include that apredetermined time has elapsed since the start of charging/discharging.The “analysis data” is data obtained by analyzing the above-describedcharge/discharge data, and includes, for example, a “DC resistance”,“dQ/dV”, each peak position of “dQ/dV”, each peak height of “dQ/dV”,each peak width of “dQ/dV”, and the like. The “DC resistance” is anumerical value obtained by dividing a difference between the voltageand the OCV at a certain point in time by the current. The “dQ/dV” is anumerical value obtained by dividing a current value by a voltage changeper hour. The peak position, peak width, and peak height are informationon the position, width, and height of the peak in a graph in which“dQ/dV” is plotted against the current, voltage, or other parameters.

When the estimation model is generated by regression analysis, theestimation model generation unit 25 may set explanatory variables inregression analysis based on the charge/discharge data and set objectivevariables based on the charge/discharge data, for example. Inparticular, in the regression analysis, the estimation model generationunit 25 may include a parameter based on the post-discharge OCV includedin the charge/discharge data in an explanatory variable of theestimation model. The parameter may be, for example, “OCV afterdischarge” showing good linearity with a degradation indicator asdescribed later, and in particular, only the “post-discharge OCV” may bean explanatory variable of the estimation model. In this case, theestimation model substantially becomes a graph or table showing therelationship between the “OCV after discharge” and the degradationindicator. Alternatively, the parameter may be, for example, “OCV aftercharge-OCV after discharge” showing good linearity with a degradationindicator as described later, and in particular, only “OCV aftercharge-OCV after discharge” may be an explanatory variable of theestimation model. In this case, the estimation model substantiallybecomes a graph or table showing the relationship between the “OCV aftercharge-OCV after discharge” and the degradation indicator. Further, inparticular, in the regression analysis, the estimation model generationunit 25 may include the degradation indicator included in thecharge/discharge data in the objective variable of the estimation model.The degradation indicator may be, for example, the “charge/dischargecapacity” of the lithium secondary battery 101, or “SOH (State ofHealth)” which is a ratio obtained by dividing the “charge/dischargecapacity” by the “initial charge/discharge capacity”. Incidentally, thecharge/discharge data generation unit 407 of the BMS 400 may arbitrarilyconfigure the charge/discharge data as long as the estimation modelgeneration unit 25 of the server device 20 includes the above-mentionedexplanatory variables and objective variables handled in the regressionanalysis.

When the estimation model is generated by machine learning, theestimation model generation unit 25 may set the input in machinelearning based on the charge/discharge data and set the output inmachine learning based on the charge/discharge data, for example. In themachine learning, the estimation model generation unit 25 may include aparameter based on the post-discharge OCV included in thecharge/discharge data in the input of the estimation model. Theparameter may be, for example, “OCV after discharge” or “OCV aftercharge-OCV after discharge”.

Incidentally, in addition to the above-described charge/discharge data,the estimation model generation unit 25 may generate an estimation modelbased on the information on the specifications of the battery module100, the charger 200, and the load 300, etc. managed by each BMS 400.For example, when the estimation model is generated by regressionanalysis, the estimation model generation unit 25 may, for example, addat least part of the information about these specifications to theexplanatory variables in the regression analysis. Further, when theestimation model is generated by machine learning, the estimation modelgeneration unit 25 may include, for example, at least part of theinformation regarding these specifications in the input in machinelearning.

Here, description will be made about the linearity of the degradationindicator of the lithium secondary battery 101 with reference to FIGS. 7and 8 . When the negative electrode 13 does not contain the negativeelectrode active material as in the lithium secondary battery 101according to the present embodiment, the present inventors have foundthat the parameter based on the OCV after discharge indicates goodlinearity with the degradation indicator of the lithium secondarybattery 101.

FIG. 7 is a diagram showing characteristic information of the “OCV afterdischarge” and “SOH” of the lithium secondary battery 101 according tovarious examples. Each example whose conditions are as shown in Table 1below may be defined by battery conditions, operating conditions, andthe like. The battery conditions may include the configurations of apositive electrode weight (mg/cm2) and a separator. Further, theoperating conditions may include a charging rate (C) and a dischargingrate (C). Incidentally, all upper limit voltages (voltages for stoppingcharging) were assumed to be 4.2 V, and all lower limit voltages(voltages for stopping discharging) were assumed to be 3 V. In Table 1,the separator “A” represents a polyethylene-based separator coated withPVDF.

TABLE 1 Battery Conditions Operating Conditions Positive Charging RateElectrode Weight (C)/Discharging (mg/cm²) Separator Rate (C) Example 110 A 0.1/0.3 Example 2 10 A 0.2/0.3 Example 3 15 A 0.1/0.3 Example 4 20A 0.1/0.3 Example 5 25 A 0.1/0.3

As shown in FIG. 7 , in the post-discharge OCV-SOH characteristicinformation according to Examples 1 to 5, in any case, linearity can beseen between the “OCV after discharge” and “SOH” depending on theconditions of each example. Therefore, it can be said that the accuracyof the estimated value (e.g., SOH) of the degradation indicator by theestimation model is improved by including the “OCV after discharge” asthe explanatory variable of the estimation model when the estimationmodel is generated by regression analysis, or as the input of machinelearning when the estimation model is generated by machine learning.

FIG. 8 is a diagram showing characteristic information of the “OCV aftercharge-OCV after discharge” and the “charge/discharge capacity” of thelithium secondary battery 101 according to various examples. Theconditions of each example are as shown in Table 2 below. Each examplemay be defined by battery conditions, operating conditions, and thelike. The battery conditions may include the configurations of apositive electrode weight (mg/cm2) and a separator. Further, theoperating conditions may include a charging rate (C) and a dischargingrate (C). Incidentally, all upper limit voltages (voltages for stoppingcharging) were assumed to be 4.2 V, and all lower limit voltages(voltages for stopping discharging) were assumed to be 3 V. In Table 2,the separator “B” represents a polyethylene-based separator coated witharamid, and the separator “C” represents a polyethylene-based separatorcoated with PVDF with a thickness different from that of the separator“A”.

TABLE 2 Battery Conditions Operating Conditions Positive Charging RateElectrode Weight (C)/Discharging (mg/cm²) Separator Rate (C) Example 610 B 0.1/0.3 Example 7 10 B 0.2/0.3 Example 8 10 C 0.1/0.3 Example 9 10D 0.1/0.3 Example 10 10 E 0.1/0.3

As shown in FIG. 8 , in the “OCV after charge-OCV after discharge” and“charge/discharge capacity” according to Examples 6 to 10, in any case,linearity can be seen between the “OCV after charge-OCV after discharge”and “charge/discharge capacity”. Therefore, it can be said that theaccuracy of the estimated value (e.g., SOH) of the degradation indicatorby the estimation model is improved by including the “OCV aftercharge-OCV after discharge” as the explanatory variable of theestimation model when the estimation model is generated by regressionanalysis, or as the input of machine learning when the estimation modelis generated by machine learning.

The estimation unit 26 acquires an estimated value of the degradationindicator of the lithium secondary battery 101 using the estimationmodel. The estimation unit 26 acquires, for example, charge/dischargedata from any BMS 400 constituting the management system 1 and inputsthe charge/discharge data to the estimation model to thereby acquire anestimated value of the degradation indicator of the lithium secondarybattery 101 managed by the BMS 400. The estimation unit 26 may outputthe estimated value of the lithium secondary battery 101 managed by theBMS 400 when a predetermined estimation condition is satisfied.

The notification information generation unit 27 generates predeterminednotification information based on the estimated value. Here, the contentof the notification information is not particularly limited as long asit is based on the estimated value of the degradation indicator, but itmay include, for example, information indicating the estimated value,information indicating comparison of the estimated value with apredetermined threshold, information indicating when to replace thelithium secondary battery 101, a message prompting the replacement ofthe lithium secondary battery 101, advice on the operation of thelithium secondary battery 101, and the like. Further, the notificationinformation generation unit 27 may determine a predeterminednotification condition based on the estimated value, or may generate thenotification information when it is determined that the predeterminednotification condition is satisfied.

(4) Operation Process

(4-1) Generation Process of Estimation Model

FIG. 9 is a diagram showing an example of an operation sequence of thegeneration process of the estimation model by the management system 1according to the present embodiment.

(S101) First, the charge/discharge control unit 406 of the BMS 400executes charging/discharging of the battery module 100. Thecharge/discharge control unit 406 controls the charger 200 and the load300 based on the settings related to the charging/discharging stored inthe storage unit 404, for example, to control the charging anddischarging of the battery module 100. The settings related to thecharging/discharging may include, for example, the time forcharging/discharging, the remaining capacity at the start ofcharging/discharging, the remaining capacity at the end ofcharging/discharging, the terminal voltage of the positive electrodeand/or the negative electrode at the start of charging/discharging, theterminal voltage of the positive electrode and/or negative electrode atthe end of charging/discharging, and the like. In charge/dischargecontrol, the charge/discharge control unit 406 may monitor at least anyof the current value supplied from the current sensor 102, the voltagevalue supplied from the voltage sensor 103, and the temperature valuesupplied from the temperature sensor 104.

(S102) Next, the charge/discharge data generation unit 407 of the BMS400 generates charge/discharge data based on the charge/dischargecontrol in Step S101. The charge/discharge data may have, for example,the data structure shown in FIG. 6 .

(S103) Next, the transmission/reception unit 408 of the BMS 400transmits the charge/discharge data generated in Step S102 to the serverdevice 20. The transmission/reception unit 24 of the server device 20receives the charge/discharge data from the BMS 400 and stores it in thestorage unit 22. The timing at which the transmission/reception unit 408transmits the charge/discharge data and the unit of the charge/dischargedata to be transmitted may be arbitrarily set. The timing oftransmitting the charge/discharge data is not limited in particular, butmay be, for example, when the number of cycles exceeds a predeterminedthreshold, a periodic or aperiodic specific date and time, when thecharge/discharge capacity falls below a predetermined threshold, whenthe user performs a predetermined operation via the operation unit 402,when a request from the server device 20 is received by the BMS 400,etc.

(S104) Next, the estimation model generation unit 25 of the serverdevice 20 generates an estimation model based on the charge/dischargedata supplied from each BMS 400 at a predetermined timing. Theestimation model generation unit 25 may generate an estimation model asa regression formula model by, for example, performing a regressionanalysis based on the charge/discharge data supplied from each BMS 400.Alternatively, the estimation model generation unit 25 may generate anestimation model as a machine-learned model by, for example, performingmachine learning based on the charge/discharge data supplied from eachBMS 400. The timing to generate the estimation model is not limited inparticular, but may be a periodic or aperiodic specific date and time,or the like.

(4-2) Estimation Process of Degradation Indicator

FIG. 10 is a diagram showing an example of an operation sequence of anestimation process of the degradation indicator by the management system1 according to the present embodiment.

(S201) First, when the predetermined conditions for estimation of thedegradation indicator for the predetermined BMS 400 are met, theestimation unit 26 of the server device 20 outputs the estimated valueof the degradation indicator of the lithium secondary battery 101managed by the predetermined BMS 400 using the estimation model. Here,the predetermined conditions for estimating the degradation indicatorare not particularly limited, but may include, for example, thereception of charge/discharge data from the predetermined BMS 400, thearrival of a periodic or aperiodic specific date and time, the receptionof a request from the predetermined BMS 400 by the server device 20, andthe like.

(S202) Next, the notification information generation unit 27 of theserver device 20 generates notification information based on theestimated value of the degradation indicator generated in Step S201.Here, the content of the notification information is not limited inparticular as long as it is based on the estimated value of thedegradation indicator, but may include, for example, informationindicating the estimated value, information indicating comparison of theestimated value with a predetermined threshold, information indicatingthe time when to replace the lithium secondary battery 101, a messageprompting the replacement of the lithium secondary battery 101, adviceon the operation of the lithium secondary battery 101, and the like.

(S203) Next, the transmission/reception unit 24 of the server device 20transmits the generated notification information to the predeterminedBMS 400 described above. The transmission/reception unit 408 of thepredetermined BMS 400 receives the notification information from theserver device 20.

(S204) Next, the output control unit 409 of the BMS 400 causes theoutput unit 403 to output various information. For example, when theoutput unit 403 is configured as a display unit, the output control unit409 generates video data or image data based on the notificationinformation and causes the display unit to display a video based on thevideo data, an image based on the image data, or the like. Further, whenthe output unit 403 is configured as an audio output unit, the outputcontrol unit 409 generates audio data based on the notificationinformation and causes the audio output unit to output audio. Thus, asthe content of the notification information, information indicating theestimated value, information indicating the comparison of the estimatedvalue with a predetermined threshold, information indicating the timewhen to replace the lithium secondary battery 101, a message promptingthe replacement of the lithium secondary battery 101, etc. are outputfrom the output unit 403.

FIG. 11 is a diagram showing an example of a screen 1000 of notificationinformation displayed on the display unit when the output unit 403 isconfigured as the display unit. As shown in FIG. 11 , the screen 1000may include an estimated value of a degradation indicator such as thecharge/discharge capacity or SOH. Further, as shown in FIG. 11 , thescreen 1000 may include information such as the number of usable cyclesand a guideline for replacement as information based on the estimatedvalue of the degradation indicator.

The embodiments described above are for facilitating the understandingof the present invention, and are not intended to limit theinterpretation of the present invention. Each element included in theembodiment and its arrangement, material, condition, shape, size, andthe like are not limited to those exemplified, and can be appropriatelychanged. Further, the configurations shown in the different examples canbe partially replaced or combined.

What is claimed is:
 1. An information processing device comprising: afirst reception unit which receives from a plurality of secondarybattery management systems, charge/discharge data of secondary batteriesmanaged by the secondary battery management systems; and an estimationmodel generation unit which generates an estimation model for estimatinga degradation indicator indicating a state of degradation of thesecondary battery based on the charge/discharge data.
 2. The informationprocessing device according to claim 1, wherein the secondary batterydoes not contain an active material in a negative electrode.
 3. Theinformation processing device according to claim 1, wherein theestimation model generation unit generates the estimation model as aregression formula model by executing a regression analysis based on thecharge/discharge data.
 4. The information processing device according toclaim 3, wherein the estimation model generation unit includes aparameter based on a post-discharge open circuit voltage (OCV) includedin the charge/discharge data in an explanatory variable of theestimation model in the regression analysis.
 5. The informationprocessing device according to claim 4, wherein the parameter is an OCVafter discharge.
 6. The information processing device according to claim5, wherein the estimation model generation unit sets only the OCV afterdischarge as an explanatory variable of the estimation model in theregression analysis.
 7. The information processing device according toclaim 4, wherein the parameter is OCV after charge-OCV after discharge.8. The information processing device according to claim 7, wherein theestimation model generation unit sets only the OCV after charge-OCVafter discharge as an explanatory variable of the estimation model inthe regression analysis.
 9. The information processing device accordingto claim 1, wherein the estimation model generation unit generates theestimation model as a machine-learned model by executing machinelearning based on the charge/discharge data.
 10. The informationprocessing device according to claim 9, wherein the estimation modelgeneration unit includes a parameter based on a post-discharge opencircuit voltage (OCV) included in the charge/discharge data in the inputof the estimation model in the machine learning.
 11. The informationprocessing device according to claim 10, wherein the parameter is an OCVafter discharge.
 12. The information processing device according toclaim 10, wherein the parameter is OCV after charge-OCV after discharge.13. The information processing device according to claim 1, furtherincluding: a second reception unit which receives from one of thesecondary battery management systems, charge/discharge data of asecondary battery managed by the one secondary battery managementsystem; an estimation unit which inputs the charge/discharge dataacquired from the one secondary battery management system to theestimation model to acquire an estimated value of a degradationindicator of the secondary battery managed by the one secondary batterymanagement system; a notification information generation unit whichgenerates notification information based on the acquired estimatedvalue; and a transmission unit which transmits the notificationinformation to the one secondary battery management system.
 14. Theinformation processing device according to claim 13, wherein thenotification information includes at least either of informationindicating the estimated value and a message related to the secondarybattery based on the estimated value.
 15. The information processingdevice according to claim 13, wherein the notification informationgeneration unit determines a predetermined notification condition basedon the estimated value, and generates the notification information whenthe notification condition is determined to be satisfied.
 16. Theinformation processing device according to claim 1, wherein each of thesecondary battery management systems manages a second battery whosenegative electrode does not contain a negative electrode activematerial.
 17. An information processing method comprising the steps ofcausing a computer to execute: receiving from a plurality of secondarybattery management systems, charge/discharge data of secondary batteriesmanaged by the secondary battery management systems; and generating anestimation model for estimating a degradation indicator indicating astate of degradation of the secondary battery based on thecharge/discharge data.
 18. A program for allowing a computer to functionas: a first reception unit which receives from a plurality of secondarybattery management systems, charge/discharge data of secondary batteriesmanaged by the secondary battery management systems; and an estimationmodel generation unit which generates an estimation model for estimatinga degradation indicator indicating a state of degradation of thesecondary battery based on the charge/discharge data.